(a) Field of the Invention
The present invention relates to an apparatus and method for transmitting data, and an apparatus and method for receiving data. More specifically, the present invention relates to an apparatus and method for transmitting data and an apparatus and method for receiving data in a transport network.
(b) Description of the Related Art
In an optical transport network, forward error correcting (hereinafter referred to as “FEC”) is performed in order to increase transmission performance. Thereby, one optical transport unit (OTU) is configured to include an optical channel data unit (hereinafter referred to as “ODU”) that corresponds to information data including overhead and payload information data, and parity bytes for correcting the ODU.
Meanwhile, in order to rapidly transmit OTU3, which shows a bit rate of approximately 43.018 Gbit/s in the related art, at a high speed, a method for transmitting OTU3 through a single optical channel by applying a simple modulation scheme such as non-return-to-zero (NRZ), differential phase shift keying (DPSK), etc., in a single wavelength has been used.
Currently, studies of high-speed transmission, such as OTU4 showing a bit rate of approximately 111.8 Gbit/s as well as OTU3, has been undertaken. However, this has problems of a technical limit of an optical module, high price, etc. As a result, a method for transmitting data in parallel through a multi-channel is being considered. As methods for transmitting data in parallel through a multi-channel, a method for transmitting data using different wavelengths for each channel, a method for transmitting data through different optical fibers or optical/electric cables for each channel, a method for transmitting through one optical wavelength and optical fiber but transmitting several bits per symbol using a polarization multiplexing and multi-level modulation scheme, etc., are used.
Meanwhile, in order to transmit data through the multi-channel in the related art, a method that distributes the OTU to each channel in a bit unit and transmits and receives it has been used. However, in the case of using the method, it is difficult to restore the OTU signal at a receiving end due to the occurrence of the delay difference for each channel upon transmitting data. In addition, even though the delay is compensated externally, since a parity byte is also assigned to each channel in bit units upon transmitting the OTU, the inter-channel error correcting performance has been affected.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention, and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.